feat(updates): detect the newest release and self-apply it, including plugin installs

Update detection was a commit count against the default branch, which says nothing about whether a *version* shipped and is pure noise on the plugin cache (a depth-1 clone, where every distance is a graft artefact). It now reads the forge's own releases API and compares the published tag to this install's package.json version, falling back to the commit count only when no release can be read — with the reason in release_check, so "up to date" never silently means "we could not look".

Two states a commit count cannot express: dev_build (ahead of the newest release, missing nothing from it) now reads "Dev build - N ahead" instead of a false "Up to date"; and on a shallow clone every commits_*_release field is null and dev_build is never asserted, because the numbers would be meaningless.

POST /api/updates/apply gains a second mode, chosen by install kind and never by the request body. A checkout still fast-forwards onto the release tag, rebuilds and self-restarts. A ~/.claude/plugins/cache/ install is refused by applyUpdate (that directory is Claude Code's to replace) and handed instead to a detached chain: claude plugin marketplace update -> claude plugin update -y -> plugin-bootstrap.js --force from the NEW cache dir, which retires this server and starts its replacement. Both write the HTTP response before anything stops the process.

The chain records every outcome to plugin-update.json in the runtime dir, outside the cache the update replaces, so the next server reports it as last_plugin_update: a failed chain is otherwise indistinguishable from a slow one, and the tab would poll a server that never returns. /reload-plugins is deliberately not in the chain - it is REPL-scoped to the session that runs it, so no background process can perform it, and plugin-bootstrap derives PLUGIN_ROOT from its own __dirname, which is what makes it unnecessary for the dashboard.

Also rebrands the sidebar subtitle, splash and page title to SmartGift Solution, and corrects three ARCHITECTURE.md statements that claimed /apply did not exist.

Verified: server 1683/1683, client 486/486, build, prettier, file-header audit, openapi.yaml regenerated.

ARCHITECTURE.md

@@ -344,7 +344,9 @@ graph TD
 | `server/lib/scoped-stats.js` | Source-scoped variants of the stats/analytics aggregates, used **only** when a `?sources=` scope filter is active — the unscoped fast paths in `routes/stats.js` / `routes/analytics.js` are untouched when no scope is set |
 | `lib/cc-discovery.js`     | Read-only discovery of every Claude Code config surface for the Config Explorer page. Pure file reads; never writes. Surfaces: skills (`<root>/skills/<name>/SKILL.md`), subagents (`<root>/agents/*.md`), slash commands (`<root>/commands/*.md`), output styles (`<root>/output-styles/*.md`), plugins (`<CLAUDE_HOME>/plugins/installed_plugins.json` joined with `enabledPlugins` in settings + per-plugin `contributes` counts **and** `contributes.items`, which names every skill / subagent / command / output style the plugin ships — each surface read from the conventional install subdirectory *and* from whatever path `plugin.json` declares for that key, with declared paths outside the plugin's own install dir dropped by `isUnder()`, so a plugin that lists its commands explicitly and keeps `commands/` empty no longer reports zero + `plugin.json` metadata), marketplaces (`known_marketplaces.json` enriched with each `marketplace.json`), MCP servers (top-level + per-project from `~/.claude.json`), hooks (across user / project / project-local settings.json), keybindings (`<CLAUDE_HOME>/keybindings.json`), statusline config + `statusline.py` / `statusline-command.sh` content, hook scripts dir (`<CLAUDE_HOME>/hooks/`), settings (with secret-key redaction matching `/token\|secret\|password\|api[_-]?key\|auth/i`), memory (`CLAUDE.md` at user + project **plus** the per-project file-based auto-memory store — every `*.md` under `~/.claude/projects/<slug>/memory/`, returned as `scope:"auto-memory"` items carrying `project`, `name`, `isIndex`, and parsed `frontmatter`, so a `MEMORY.md` index and one file per remembered fact, often 100+, all surface). Path containment via `isUnder()` — every read must resolve under CLAUDE_HOME, project `.claude/`, or be a project CLAUDE.md. 256 KB read cap. Minimal YAML frontmatter parser handles `key: value` + quoted strings + indented continuation lines |
 | `lib/cc-mutate.js`        | Create / overwrite / delete for the **low-risk text-file surfaces only** (skills, subagents, slash commands, output styles, memory — including the per-project file-based auto-memory store, mutated via `scope: "auto-memory"`, `type: "auto-memory"`, `project`, `name`, with its backups landing in `<memory-dir>/.cc-config-backups/auto-memory/`), plus `writeKeybindings()` for the structured `keybindings.json` editor (read-modify-write that preserves top-level metadata, rejects duplicate contexts/keys, and backs up to `<CLAUDE_HOME>/cc-config-backups/keybindings/`). Plugins, MCP, hooks-in-settings, and `settings.json` files are NEVER written from here — they have concurrent-write races with the live Claude Code CLI. Every mutation creates a timestamped backup at `<root>/cc-config-backups/<type>/<base>.<ISO>.bak[.dir]` BEFORE the change — backups land outside the directories Claude Code scans, so a deleted skill cannot resurface as a backup-named one. Writes are atomic: temp file in same dir → fsync → `renameSync`. Tmp removed on every failure path. Skill dirs are backed up whole (preserving bundled assets) before recursive removal. Strict `name` regex (`^[A-Za-z0-9][A-Za-z0-9._-]{0,63}$`), 256 KB content cap, double-checked path containment via `isUnder()` |
-| `routes/cc-config.js`     | HTTP surface for the Claude Config Explorer. Read endpoints for every surface (skills, agents, commands, output-styles, plugins, marketplaces, mcp, hooks, hook-scripts, keybindings, statusline, settings, memory, file, overview), plus mutation endpoints (`PUT /file`, `DELETE /file`, and a structured `PUT /keybindings`) that delegate to `cc-mutate.js`, plus a `GET /backups` listing for the recovery modal, plus the auth-profile routes (`GET/POST/PATCH/DELETE /profiles`, `POST /profiles/activate`) that delegate to `cc-profiles.js`. After every successful PUT/DELETE the route broadcasts `cc_config_changed` over the WebSocket so any open `/cc-config` tab refetches without polling. All errors return structured `{error: {code, message}}` shapes mapped to 400/404/413/500 statuses |
+| `lib/cc-reload.js`        | Types `/reload-plugins` / `/reload-skills` into the Claude Code sessions the dashboard already has open, over `tmux send-keys` (reusing `tmux.js`'s `sendText`). Both slash commands are scoped BY CLAUDE CODE to the session that runs them, so a session cannot be reloaded from the outside and no background process can do it on a session's behalf — typing into a live pane is the only real mechanism. Deliberately spawns NO `claude` process: a one-shot `claude -p "/reload-plugins"` would reload only its own short-lived session, exit, and leave a junk session in the dashboard's history, so this module creates no sessions at all. Skips panes sitting at a shell prompt (the text would run as a shell command) and addresses `claude` lanes only, since Codex has no such command. Sends to a busy pane on purpose — tmux queues the keystrokes into the REPL's input buffer, so a late reload still lands, where skipping busy panes would leave exactly the sessions in active use running stale code. The command set is a fixed constant, never caller-supplied: a pane's stdin is an arbitrary-code boundary. Never throws |
+| `lib/cc-update-all.js`    | Starts and reports on the "Update all" batch, whose work lives in the detached `scripts/cc-update-all-helper.js`. Detached for a structural reason: the batch ends with the plugin THIS dashboard runs from, and that step's `plugin-bootstrap.js --force` SIGTERMs this very server, so an in-process loop would die with the remaining plugins unrun and nothing left to report. Order is marketplaces → every other plugin → AgentHub last → one reload. The worker journals every step transition to `cc-update-all.json` under the runtime dir — outside the plugin cache the update replaces — so whichever server is alive can serve progress from it; the POST's response is only an acknowledgement. `readUpdateAll()` DERIVES an `abandoned` status for a `running` journal older than `STALE_MS` (1 h), because a detached worker killed by a reboot leaves nobody to write the terminal entry and the button would otherwise stay wedged forever. `isRunning()` gates a concurrent batch, since two `claude plugin update` chains over one config dir race |
+| `routes/cc-config.js`     | HTTP surface for the Claude Config Explorer. Read endpoints for every surface (skills, agents, commands, output-styles, plugins, marketplaces, mcp, hooks, hook-scripts, keybindings, statusline, settings, memory, file, overview), plus mutation endpoints (`PUT /file`, `DELETE /file`, and a structured `PUT /keybindings`) that delegate to `cc-mutate.js`, plus a `GET /backups` listing for the recovery modal, plus the auth-profile routes (`GET/POST/PATCH/DELETE /profiles`, `POST /profiles/activate`) that delegate to `cc-profiles.js`, plus the install-wide update surface: `GET/POST /plugins/update-all` (a DETACHED batch — every marketplace, then every plugin, then a reload, with THIS dashboard's own plugin last because its bootstrap restarts the server; progress is polled from an on-disk journal, never from the POST's response) and `POST /reload` (types `/reload-plugins`+`/reload-skills` into the live lane panes; see `cc-reload.js`). After every successful PUT/DELETE the route broadcasts `cc_config_changed` over the WebSocket so any open `/cc-config` tab refetches without polling. All errors return structured `{error: {code, message}}` shapes mapped to 400/404/413/500 statuses |
 | `lib/cc-profiles.js`      | Named Claude Code **auth profiles** — swap which Anthropic account (and therefore which quota) the local `claude` CLI runs as. A profile is exactly two identity artifacts: `claudeAiOauth` out of `<CLAUDE_HOME>/.credentials.json`, and `oauthAccount` + `userID` out of the `.claude.json` config file(s) (`<CLAUDE_HOME>.json` and `<CLAUDE_HOME>/.claude.json`, each key-merged in place and only when it already exists, so `projects`/`numStartups`/everything else survives). Skills, subagents, commands, memory, plugins, marketplaces, MCP servers and settings are never read or written here — that is what makes a switch keep the whole workspace and change only the account; `mcpOAuth` stays put too (machine MCP tokens, not account identity). Stored one JSON file per profile under `<CLAUDE_HOME>/agenthub-profiles/` (dir `0700`, files `0600`), holding live OAuth tokens, so **no route ever returns token material** — `listProfiles()` answers identity metadata only. A profile carries two names: `name`, the filename and the id every route takes, and `label`, the free-form display name (spaces and diacritics fine, since it never touches a path) that `renameProfile()` edits in place without moving the file. One account is one profile — `saveProfile()` refuses `EDUPLICATE` rather than making a second copy, because duplicates both report themselves active, and `deleteProfile()` blocks only the LAST copy of the live account so a duplicate stays cleanable. Cannot mint credentials (only `claude auth login` can): a new profile is captured by logging in, then snapshotting. `activateProfile()` re-snapshots the outgoing account first so refreshed tokens are not lost, and refuses (`EUNSAVED`) to switch away from an account that was never saved — that would discard the only copy of its credentials. Atomic temp + rename at `0600` |
 | `lib/cc-watcher.js`       | Best-effort `fs.watch` over `~/.claude/` (recursive where the platform / Node version honors it — macOS / Windows always; Linux from Node 20) plus `~/.claude.json`. Coalesces bursts at 500 ms and broadcasts `cc_config_changed` with `{ source: "fs", paths: [...] }` so the Config Explorer picks up changes from external tools (CLI installs a plugin, manual `settings.json` edits, dropping a new skill) without a manual refresh. Started from `server/index.js` after the HTTP server boots; failures are caught and logged so a flaky watcher can't take the server down |
 | `lib/codex-discovery.js`  | Read-only discovery of the Codex CLI's file-backed config surfaces for the Codex Config panel — the Codex counterpart of `cc-discovery.js`. Surfaces: skills (`<root>/skills/<name>/SKILL.md`), agents (`<root>/agents/*.toml`), rules (`<root>/rules/*`), memory (`AGENTS.md` at user `~/.codex` + project root), config (`config.toml` at user + project `.codex/`). No filesystem watcher counterpart to `cc-watcher.js` exists for Codex. `readFileSafe()` re-validates path containment (leaf/ancestor symlink-escape guard) independent of the write side's own check. Codex's scope union is `"user"` \| `"project"` only — it has no `"project-local"` settings layer and no per-project file-based auto-memory store |
@@ -1961,15 +1963,26 @@ These behaviors are reinforced by explicit `Cache-Control` headers from the prod
 
 ## Update Notifier Subsystem
 
-The Update Notifier is a **detection-only** subsystem that tells the user when the dashboard's git checkout is behind its tracked upstream branch. It never mutates the checkout or restarts the server — those actions are intentionally left to the user in a terminal, because a process cannot reliably replace itself without an external supervisor.
+The Update Notifier tells the user when a newer **release** of the dashboard has been published, and — on an ordinary git checkout that can be fast-forwarded — can apply it on one click.
+
+The version signal is the forge's own release list, read over REST at `/api/v1/repos/<owner>/<repo>/releases/latest` with the owner and repo derived from the `origin` remote URL (no hardcoded host, no credentials for a public repo). The published tag is compared against this install's `package.json` version. When no release can be read — a non-HTTP remote, an offline machine, a repo with no releases — detection falls back to the original commit count against the canonical default branch and puts the reason in `release_check`, so "up to date" never means "we couldn't look".
+
+Two states the release model makes visible that a commit count cannot:
+
+- **`dev_build`** — the install is strictly ahead of the newest release and missing nothing from it. It is a build off the branch, not a shipped version, and the Sidebar says so instead of "Up to date".
+- **`plugin_managed`** — the install runs from `~/.claude/plugins/cache/`. Claude Code owns that directory and replaces it wholesale, so `applyUpdate` will not rewrite it: it refuses with `reason: "plugin_managed"`, decided from the path before any status lookup so the refusal holds offline too. A self-pull would leave a cache directory whose name (a commit sha) no longer matched its contents. **The button still works here**, by a different route: `POST /api/updates/apply` catches that refusal and hands the job to the detached chain in `server/lib/plugin-update.js` — `claude plugin marketplace update <mkt>` → `claude plugin update <plugin>@<mkt> -y` → `plugin-bootstrap.js --force` **from the new cache directory**, which stops this server and starts the new one. It answers `200 {applied:true, mode:"plugin"}`. The one thing no background process can do is `/reload-plugins`: that is a REPL action scoped to the session that runs it, so an already-open Claude Code session still needs it for new skills/commands/hooks. The dashboard does not, because `plugin-bootstrap.js` derives `PLUGIN_ROOT` from its own `__dirname` rather than from `${CLAUDE_PLUGIN_ROOT}`.
+
+A **shallow clone** (`--depth`) is the third special case, and the plugin cache is one: history is grafted, so every commit-distance number is a graft artefact rather than a distance. All `commits_*_release` fields are `null` there and `dev_build` is never asserted; the version string is the only signal used.
 ### Module Layout
 
 ```mermaid
 graph TD
     subgraph Server
-        LIB["update-check.js<br/>getUpdatesStatus"]
+        LIB["update-check.js<br/>getUpdatesStatus + applyUpdate<br/>forge releases API"]
         SCHED["update-scheduler.js<br/>startUpdateScheduler"]
-        ROUTE["routes/updates.js<br/>GET status, POST check"]
+        ROUTE["routes/updates.js<br/>GET status, POST check, POST apply"]
+        PLUG["lib/plugin-update.js<br/>schedulePluginUpdate"]
+        HELPER["scripts/plugin-update-helper.js<br/>detached: claude plugin update<br/>then plugin-bootstrap --force"]
         WS["websocket.js<br/>broadcast update_status"]
     end
 
@@ -1982,6 +1995,9 @@ graph TD
 
     SCHED -->|tick every 5 min| LIB
     ROUTE -->|on request| LIB
+    ROUTE -->|apply, plugin install| PLUG
+    PLUG -->|spawn detached| HELPER
+    HELPER -->|verdict file| LIB
     SCHED -->|fingerprint changed| WS
     ROUTE -->|on POST check| WS
     WS -->|update_status frame| API
@@ -2041,11 +2057,12 @@ sequenceDiagram
 
 | Component | Responsibility |
 | --- | --- |
-| **`server/lib/update-check.js`** | Pure function `getUpdatesStatus(root?, { skipFetch? })`. Runs every git call via `execFile` (no shell, 10s–120s timeouts). **Branch- and fork-aware:** prefers `upstream` over `origin` when both exist (standard fork convention), resolves `<remote>/master`/`/main`/`/HEAD`, reads the current branch and its tracked upstream, and shapes `manual_command` per situation: `git pull --ff-only` only when the local branch tracks the canonical ref; `git fetch <remote> && git merge --ff-only <ref>` for forks (local branch name matches canonical but tracks a different remote); `git fetch <remote>` only on a feature branch or detached HEAD. Non-git installs, missing remotes, fetch failures, and unresolvable upstream refs are returned as soft payloads — never throws. Adds `situation`, `situation_note`, `canonical_remote`, `current_branch`, `tracking_upstream`, and `tracks_canonical` to the response. |
+| **`server/lib/update-check.js`** | `getUpdatesStatus(root?, { skipFetch?, latestRelease? })` + `applyUpdate(root?)`. Runs every git call via `execFile` (no shell, 10s–120s timeouts) and reads the newest release over `fetch` with an `AbortSignal.timeout` — `fetchLatestRelease` NEVER throws, resolving to `{ok:false, reason}` (`no_remote`, `remote_not_http`, `no_releases`, `unreachable`, `bad_payload`, `http_<status>`) so a status poll degrades instead of erroring. `releaseApiUrl` derives the endpoint from the remote (https, scp-style and `ssh://` forms) and returns null for anything not owner/repo shaped, which is what keeps local-path remotes off the network entirely. `compareVersions` orders numeric triples and strips a leading `v`, since this repo carries both `v1.5.0` and `1.4.6`. `isShallowClone` gates every commit-distance calculation; `detectPluginInstall` reads the marketplace and plugin name out of the cache path. **Branch- and fork-aware** as before: resolves `<remote>/master`/`/main`/`/HEAD`, reads the current branch and its tracked upstream, and shapes `manual_command` per situation — the `claude plugin ...` commands for `plugin_managed`; `git fetch <remote> --tags && git merge --ff-only <tag>` for `release_available`; `git pull --ff-only` when the branch tracks the canonical ref; `git fetch <remote> && git merge --ff-only <ref>` for forks; `git fetch <remote>` only on a feature branch or detached HEAD. Non-git installs, missing remotes, fetch failures, and unresolvable upstream refs are returned as soft payloads — never throws. |
 | **`server/update-scheduler.js`** | Ticks the lib every `DASHBOARD_UPDATE_CHECK_INTERVAL_MS` (default 300 000, floor 60 000). First tick is scheduled 8s after server start with `.unref()` so it doesn't block shutdown. Broadcasts only when the fingerprint `{update_available, remote_sha, commits_behind, fetch_error, manual_command}` changes — `manual_command` is included so situation transitions (e.g. user switches branches, or adds an `upstream` remote) trigger a re-broadcast even when the SHA and commit count are unchanged. Emits a framed message to stdout on "up-to-date → behind" transitions, and only suggests "restart the dashboard" when the printed command actually rewrites the working tree. `DASHBOARD_UPDATE_CHECK=0\|false\|off` disables the scheduler entirely. |
-| **`server/routes/updates.js`** | Two endpoints: `GET /status` (read-only check), `POST /check` (check + broadcast). Mounted under `/api/*`, so they ride the default loopback bind as their trust boundary and are gated by `DASHBOARD_TOKEN` when one is set. There is **no** `POST /apply` route. |
-| **`UpdateNotifier.tsx`** | Modal. Hydrates from `api.updates.status()` on mount and mirrors the payload back into the local `eventBus` so the Sidebar can listen without a second git fetch. Subscribes to `update_status` WS frames for ongoing sync. Keeps `dismissedSha` in `localStorage` (`agent-monitor-update-dismissed-sha`) and in React state; a window event `dashboard:reset-update-dismissal` from the Sidebar clears both. ESC / backdrop click dismisses. |
-| **`Sidebar.tsx`** | Always-visible "Check for updates" button in the footer. Subscribes to `update_status` (no own fetch). On click: clears dismissed SHA in localStorage, dispatches `dashboard:reset-update-dismissal`, then calls `api.updates.check()`. Visual state: emerald badge when `update_available`, amber when `fetch_error`, neutral otherwise. |
+| **`server/routes/updates.js`** | Three endpoints: `GET /status` (read-only check), `POST /check` (check + broadcast), `POST /apply`. `/apply` has **two modes**, chosen by how this copy was installed, never by the request body: **checkout** — fast-forward onto the release tag, `npm run setup`, `npm run build` in production, then `scheduleRestart()`; **plugin** — `applyUpdate`'s `plugin_managed` refusal is caught and `schedulePluginUpdate()` runs instead, answering `200 {applied:true, mode:"plugin"}`. The plugin branch fires only when there is genuinely something to pull (`update_available` plus a marketplace and plugin name parsed from the cache path) — a `plugin_managed` refusal with nothing newer published stays a 409 rather than spawning a chain that would stop the server for nothing. Otherwise 409 `UPDATE_NOT_APPLICABLE` with `reason` `"up_to_date"`, `"not_fast_forwardable"`, or `"plugin_managed"`. Both modes write the response BEFORE anything stops the process. Mounted under `/api/*`, so all three ride the default loopback bind as their trust boundary and are gated by `DASHBOARD_TOKEN` when one is set. |
+| **`server/lib/plugin-update.js`** + **`scripts/plugin-update-helper.js`** | The plugin-cache update chain. The lib only spawns the helper detached (cwd = the runtime dir, **not** the plugin root, which is about to be superseded) and clears any previous verdict first so a stale success can't be read back as this run's result. All work is in the helper because its last step SIGTERMs the server that asked for the update — the same split as `self-restart.js`, one step further. The helper re-validates the marketplace and plugin names against `/^[A-Za-z0-9][\w.-]*$/` (they reach an argv across a process boundary), resolves `claude` on PATH or at `~/.local/bin/claude` (a hook-spawned server does not inherit the login shell's PATH), picks the newest cache directory that isn't the old root and does contain `scripts/plugin-bootstrap.js`, and records **every** outcome — including an unexpected throw — to `plugin-update.json` under `~/.claude/agenthub/runtime/`, outside the cache so it survives the swap. Steps: `validate`, `resolve_claude`, `marketplace_update`, `plugin_update`, `already_current` (`ok:true`; nothing was pulled and the old server was left running), `bootstrap`, `done`. `readLastPluginUpdate()` surfaces it as `last_plugin_update` on the status payload — without it a failed chain is indistinguishable from a slow one. |
+| **`UpdateNotifier.tsx`** | Modal. Hydrates from `api.updates.status()` on mount and mirrors the payload back into the local `eventBus` so the Sidebar can listen without a second git fetch. Subscribes to `update_status` WS frames for ongoing sync. Keeps the dismissal key in `localStorage` (`agent-monitor-update-dismissed-sha`) and in React state — the **release tag** when one was read, else the upstream SHA, so a newer release re-opens the prompt while a dismissed one stays dismissed; a window event `dashboard:reset-update-dismissal` from the Sidebar clears both. ESC / backdrop click dismisses. |
+| **`Sidebar.tsx`** | Always-visible "Check for updates" button in the footer. Subscribes to `update_status` (no own fetch). On click: clears dismissed SHA in localStorage, dispatches `dashboard:reset-update-dismissal`, then calls `api.updates.check()`. Visual state: emerald badge when `update_available`, amber when `fetch_error`, neutral otherwise. Label has four resting states, not two — `"<tag> available"`, `"Dev build · N ahead"` (when `dev_build`), `"Up to date"`, or `"Check for updates"` before the first result. |
 
 ### Payload Shape
 
@@ -2060,6 +2077,8 @@ interface UpdateStatusPayload {
   tracking_upstream?: string | null;   // e.g. "origin/feature/foo", null if no upstream
   tracks_canonical?: boolean;          // true when branch upstream === remote_ref
   situation?:                          // categorical hint for the UI
+    | "plugin_managed"                 // ~/.claude/plugins/cache — /apply delegates
+    | "release_available"              // fast-forward onto the release tag
     | "tracking_canonical"
     | "fork_or_diverged_tracking"
     | "feature_branch"
@@ -2071,10 +2090,37 @@ interface UpdateStatusPayload {
   manual_command?: string | null;      // shaped for the user's situation
   message?: string | null;
   fetch_error?: string;                // set when git fetch fails
+
+  // ── Release layer ──
+  install_kind?: "plugin" | "checkout";
+  plugin_marketplace?: string | null;  // "sg" — parsed from the cache path
+  plugin_name?: string | null;         // "agenthub" — same source
+  last_plugin_update?: {               // verdict of the previous chain, if any
+    ok: boolean;
+    step: string;                      // "validate" | "resolve_claude" | ...
+    error?: string;
+    note?: string;
+    plugin_root?: string;
+    finished_at?: string;
+  } | null;
+  local_version?: string | null;       // this install's package.json version
+  shallow_clone?: boolean;             // true => every commits_* below is null
+  release_check?: string;              // "ok" | "no_remote" | "remote_not_http"
+                                       //      | "no_releases" | "unreachable"
+                                       //      | "bad_payload" | "http_<status>"
+  latest_release?: string | null;      // tag, e.g. "v1.5.0"
+  latest_release_name?: string | null;
+  latest_release_url?: string | null;
+  latest_release_published_at?: string | null;
+  latest_release_notes?: string | null; // truncated server-side to 4000 chars
+  release_sha?: string | null;         // commit the tag resolves to locally
+  commits_behind_release?: number | null;
+  commits_ahead_of_release?: number | null;
+  dev_build?: boolean;                 // ahead of the newest release, missing nothing
 }
 ```
 
-The same shape is used by `GET /status`, `POST /check`, and the `update_status` WS message.
+The same shape is used by `GET /status`, `POST /check`, and the `update_status` WS message. `POST /apply` returns it plus `applied: boolean`; in plugin mode it also carries `mode: "plugin"` and `runtime_dir`, and on a 409 a `reason` of `"up_to_date"`, `"not_fast_forwardable"`, or `"plugin_managed"`. `update_available` and `dev_build` are never both true.
 
 ### Failure Mode Matrix
 
@@ -2085,20 +2131,29 @@ The same shape is used by `GET /status`, `POST /check`, and the `update_status`
 | `git fetch` failed (offline, auth) | `{git_repo:true, update_available:false, canonical_remote, fetch_error:"<stderr>"}` | Sidebar button goes amber; modal stays suppressed until a successful check. |
 | Canonical default branch unresolvable | `{git_repo:true, update_available:false, canonical_remote, message:"Could not resolve <remote>/master..."}` | Modal suppressed. |
 | Healthy, up to date | `{git_repo:true, update_available:false, commits_behind:0, situation:"tracking_canonical"\|...}` | Sidebar neutral, modal suppressed. |
+| Release lookup failed (offline, non-HTTP remote, no releases) | `{release_check:"unreachable"\|"remote_not_http"\|"no_releases"\|..., latest_release:null}` | Detection falls back to the commit count; the modal states the reason so "up to date" is not read as "release checked". |
+| Ahead of the newest release | `{update_available:false, dev_build:true, commits_ahead_of_release:N}` | Sidebar reads `Dev build · N ahead`; modal suppressed (a dev build is not an available update). |
+| Shallow clone (incl. the plugin cache) | `{shallow_clone:true, commits_behind_release:null, commits_ahead_of_release:null, dev_build:false}` | No commit badge is rendered at all — the numbers would be graft artefacts. Version compare still decides `update_available`. |
+| Newer release, ordinary checkout | `{update_available:true, situation:"release_available", latest_release:"vX.Y.Z", manual_command:"...git fetch origin --tags && git merge --ff-only vX.Y.Z..."}` | Modal opens titled with the release version, links its notes, and shows **Update now**. |
+| Newer release, plugin-cache install | `{update_available:true, situation:"plugin_managed", install_kind:"plugin", plugin_marketplace:"sg", plugin_name:"agenthub", manual_command:"claude plugin marketplace update sg && ..."}` | Modal opens WITH **Update now**; `POST /apply` answers `200 {applied:true, mode:"plugin"}` and the detached chain pulls the new version and re-bootstraps. The modal notes that an already-open Claude Code session still needs `/reload-plugins` for new skills/commands. |
+| Plugin chain ran but nothing was published | `{last_plugin_update:{ok:true, step:"already_current"}}` | The old server keeps running, untouched; no restart, no error banner. |
+| Plugin chain failed (no `claude` on PATH, `npm ci` broke, bootstrap died) | `{last_plugin_update:{ok:false, step:"resolve_claude"\|"plugin_update"\|"bootstrap", error:"..."}}` | Danger banner in the modal naming the failed step. A `bootstrap` failure means the old server was already stopped, so the verdict says to run `/agenthub-update` to recover — and it is read back by whichever server comes up next, because it lives outside the cache. |
+| Plugin `/apply` with nothing newer published | 409 `{reason:"plugin_managed"}` | No chain is spawned. Message points at `/agenthub-update` to force a refresh. |
 | Healthy, behind, on canonical branch | `{update_available:true, situation:"tracking_canonical", manual_command:"...git pull --ff-only..."}` | Modal opens with `git pull` flow + restart hint. |
 | Healthy, behind, fork (origin = fork, upstream = canonical) | `{update_available:true, situation:"fork_or_diverged_tracking", manual_command:"...git fetch upstream && git merge --ff-only upstream/master..."}` | Modal opens with merge flow + restart hint + `situation_note` explaining the divergence. |
 | Healthy, behind, on a feature branch | `{update_available:true, situation:"feature_branch", manual_command:"...git fetch <remote>"}` | Modal opens; `situation_note` explains the user is off the canonical branch; restart hint suppressed because the working tree isn't being changed. |
 
-### Why Detection-Only
+### Why Self-Apply Stays Narrow
 
-The dashboard does not expose an apply/restart endpoint by design. A process cannot reliably replace itself without an external supervisor, and several real constraints make an in-process self-update path strictly worse than letting the user run two commands in a terminal:
+`POST /api/updates/apply` is the one path in this dashboard that mutates its own working tree and restarts the process. It is deliberately narrow: in checkout mode it acts only on `release_available`, `tracking_canonical`, and `fork_or_diverged_tracking`, always with `--ff-only`, and refuses outright on a feature branch or a detached HEAD. A `plugin_managed` install is not a git operation at all — it is delegated to `claude plugin update`, whose own tooling owns that directory. Everywhere else the dashboard prints a command and lets the user run it, because the constraints below are real and an automatic path cannot answer them:
 
 - **Supervisor ambiguity.** `npm run dev` (concurrently), `npm start`, `pm2`, `systemd`, and `launchd` each need different restart logic; an in-process helper could only encode one of them and would silently mis-restart the rest.
 - **Silent failures.** `npm install` / `npm run build` / port-release timing issues surface as a dead server with no user-facing feedback once the original process has exited.
 - **No rollback.** A partial pull + install leaves a broken checkout with no atomic recovery — the working tree is mutated mid-flight.
-- **Branch coverage.** Even with the situation-aware `manual_command` produced by the detection layer, an automatic apply would still need branch-aware integration (rebase vs merge vs switch) and merge-conflict handling. That belongs in the user's shell, not in a background daemon.
+- **Branch coverage.** A feature branch or detached HEAD would need branch-aware integration (rebase vs merge vs switch) and merge-conflict handling. That belongs in the user's shell, not in a background daemon — which is why those situations get a printed `git fetch` and no button.
+- **Ownership.** A plugin-cache install is not ours to rewrite by hand — its directory names are content hashes Claude Code manages. So that case does not fast-forward anything; it calls `claude plugin update` and then re-runs `plugin-bootstrap.js` from the directory that tool produced. The residual limit is only `/reload-plugins`, which is REPL-scoped: an interactive session keeps its old skills/commands until the user reloads, even though the dashboard server has already moved.
 
-The detection layer carries all of the signal value: the dashboard tells the user *when* to update and *exactly what to run*; the user owns the *how* in their own shell.
+What `--ff-only` buys is the absence of the first three problems inside the supported cases: the move is either a clean fast-forward or it aborts, `npm run setup`/`build` failures reject the request before any restart is scheduled, and the restart itself goes through `self-restart.js` + the detached `scripts/restart-helper.js` rather than an in-process guess at the supervisor.
 
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